On 27/01/16 9:27 PM, "Arnd Bergmann" <arnd@xxxxxxxx> wrote:
>The qla4_83xx_rd_reg_indirect() function can fail when it is unable
>to read a register, but not all callers check its return value before
>using the register data, and gcc correctly warns about this:
>
>qla4xxx/ql4_83xx.c: In function 'qla4_83xx_process_reset_template':
>qla4xxx/ql4_83xx.c:1073:36: warning: 'value' may be used uninitialized in
>this function
> ha->reset_tmplt.array[index++] = value;
> ^
>qla4xxx/ql4_83xx.c:1050:11: note: 'value' was declared here
> uint32_t value;
> ^
>qla4xxx/ql4_83xx.c:902:8: warning: 'value' may be used uninitialized in
>this function
> value &= p_rmw_hdr->test_mask;
> ^
>qla4xxx/ql4_83xx.c:895:11: note: 'value' was declared here
> uint32_t value;
> ^
>In file included from ../include/linux/io.h:25:0,
> from ../include/linux/pci.h:31,
> from ../drivers/scsi/qla4xxx/ql4_def.h:16,
> from ../drivers/scsi/qla4xxx/ql4_83xx.c:10:
>asm/io.h:101:2: warning: 'value' may be used uninitialized in this
>function
> asm volatile("str %1, %0"
> ^
>qla4xxx/ql4_83xx.c:874:11: note: 'value' was declared here
> uint32_t value;
> ^
>
>Unfortunately, I don't see any helpful way to add proper error handling
>for this case, and the failure scenario for rd_reg seems rather obscure,
>so this bails out and makes the rd_reg accessor set the result to
>0xffffffff
>so we at least get a predictable value.
>
>Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
>---
> drivers/scsi/qla4xxx/ql4_83xx.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
>diff --git a/drivers/scsi/qla4xxx/ql4_83xx.c
>b/drivers/scsi/qla4xxx/ql4_83xx.c
>index 5d4f8e67fb25..638f72c5ab05 100644
>--- a/drivers/scsi/qla4xxx/ql4_83xx.c
>+++ b/drivers/scsi/qla4xxx/ql4_83xx.c
>@@ -46,11 +46,13 @@ int qla4_83xx_rd_reg_indirect(struct scsi_qla_host
>*ha, uint32_t addr,
>
> ret_val = qla4_83xx_set_win_base(ha, addr);
>
>- if (ret_val == QLA_SUCCESS)
>+ if (ret_val == QLA_SUCCESS) {
> *data = qla4_83xx_rd_reg(ha, QLA83XX_WILDCARD);
>- else
>+ } else {
>+ *data = 0xffffffff;
> ql4_printk(KERN_ERR, ha, "%s: failed read of addr 0x%x!\n",
> __func__, addr);
>+ }
>
> return ret_val;
> }
>--
>2.7.0
>
Acked-by: Nilesh Javali <nilesh.javali@xxxxxxxxxx>
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